PRESSURE-DEPENDENCE OF THE REACTION C2H5+O2

The rate constant of the reaction C2H5+O2→products, k1, has been measured as a function of pressure (3-1500 Torr) relative to that of C2H5+Cl2→C2H5Cl+Cl, k2 at 298 K in three diluents (N2, He, or SF6). Ethyl radicals were generated by UV irradiation of Cl2, C2H6, O2, N2 (He, SF6) mixtures. Using the literature value k1=2.9×10-12 cm3/molecule s at 5 Torr to calibrate the relative rate study, the rate constants at the high and low pressure (He diluent) limits for C2H5+O2+M=C2H5O2+M, k1a, are (k1a)∞=9.2(±0.9)×10-12 cm3/molecule s and (k1a)0=6.5(±2.0)×10-29 cm6/molecule2 s. © 1990.